Abstract
Purpose:
Null mutations in FAM161A, which encodes a protein located in the photoreceptor connecting cilium/basal body, are the major cause of retinitis pigmentosa in the Israeli population. The function of FAM161A is unknown, but this protein has been shown to interact with a number of other proteins associated with inherited retinal dystrophies. In this study, we analyzed the binary interactome of FAM161A to elucidate its possible functions in retinal physiology and in retinitis pigmentosa.
Methods:
We performed a saturated yeast-two-hybrid (Y2H) screen of human and bovine retinal cDNA libraries, using different fragments of FAM161A as baits. cDNA clones encoding putative interactors were evaluated by Sanger sequencing. Co-immunoprecipitation and proximity ligation assays (PLA) on cell lines were used to validate the newly-identified binary interactions.
Results:
We identified as many as 53 partners of FAM161A, which revealed an interactome having a statistically significant bias towards proteins of the Golgi apparatus, the centrosome, and the microtubule network. The validation of FAM161A interactions with key partners by co-immunoprecipitation and PLAs strengthens our hypothesis that FAM161A is a member of the Golgi-centrosomal interactome, a network of proteins interconnecting Golgi maintenance, intracellular transport, and centrosome organization. Notable FAM161A interactors included AKAP9, FIP3, GOLGA3, KIFC3, KLC2, PDE4DIP, NIN, and TRIP11.
Conclusions:
These findings suggest that FAM161A is at a center of a complex protein network and that its role is unlikely to be limited to ciliary tasks, but extend to more general cellular functions, highlighting possible novel mechanisms for the molecular pathology of retinal disease.